new microwave shield preparation for super high frequency range: occupational approach to radiation protection

Background: Widespread use of X-band frequency [a part of the super high frequency microwave] in the various workplaces would contribute to occupational exposure with potential of adverse health effects

According to limited study on microwave shielding for the workplace, this study tried to prepare a new microwave shielding for this purpose

Methods: We used El-403 epoxy thermosetting resin as a matrix and nickel oxide nanoparticle with the diameter of 15-35 nm as filler. The Epoxy/ Nickel oxide composites with 5, 7, 9 and 11 wt% were made in three different thicknesses [2, 4 and 6 mm]

According to transmission / reflection method, shielding effectiveness [SE] in the X-band frequency range [8-12.5 GHz] was measured by scattering parameters directly given by the 2-port Vector Network Analyzer. The fabricated composites characterized by X-ray Diffraction and Field Emission Scanning Electron Microscope

Results: The best average of shielding effectiveness in each thickness of fabricated composites obtained by 11%-2 mm, 7%-4 mm and 7%-6 mm composites with SE values of 46.80%, 66.72% and 64.52%, respectively. In addition, the 11%-6 mm, 5%-6 mm and 11%-4 mm-fabricated composites were able to attenuate extremely the incident microwave energy at 8.01, 8.51 and 8.53 GHz by SE of 84.14%, 83.57 and 81.30%, respectively

Conclusions: The 7%-4mm composite could be introduced as a suitable alternative microwave shield in radiation protection topics in order to its proper SE and other preferable properties such as low cost and weight, resistance to corrosion etc. It is necessary to develop and investigate the efficacy of the fabricated composites in the fields by future studies

Cardiac strain between normal weight and overweight workers in hot/humid weather in the persian gulf

In hot weather, overweight and obesity are considered as significant risk factors for the incidence of cardiac strain in workers. This study was aimed to compare cardiac strain among overweight and normal weight workers in hot, humid conditions in the south of Iran. This cross sectional study was conducted on 71 workers in the south of Iran in summer 2010. The heart rate was measured at rest and at actual work. Cardiac strain based on working heart rate [WHR], the relative cardiac cost [RCC], the net cardiac cost [NCC], load relative cardiovascular [CVL], and heart rate reduction was analyzed in 35 normal weight people [body mass index [BMI] <25 kg/m[2]] and 36 overweight people [BMI >25 kg/m[2]] using descriptive statistics. In 42% of the total workers, BMI was >25 kg/m[2]. The average of Wet Bulb Globe Temperature Index [WBGT Index] in the two groups was not significantly different. The mean WHR in the two groups was 101 +/- 20.3 and 112 +/- 18.9, respectively [P = 0.026]. Percentages exceeded the acceptable limits in the parameters NCC, RCC, WHR, CVL, and Brouha index, which were significantly higher in overweight people than in those with normal weight. Based on the study results, it is concluded that the severity of cardiac strain was higher in overweight workers compared with that in normal weight workers. Hence, in order to decrease the cardiac strain, selecting overweight individuals for these jobs should be avoided and also some vital intervention for losing weight should be implemented such as nutrition education and encouraging them regarding physical activity

effects of cell phone waves [900 MHz-GSM Band] on sperm parameters and total antioxidant capacity in rats

There is tremendous concern regarding the possible adverse effects of cell phone microwaves. Contradictory results, however, have been reported for the effects of these waves on the body. In the present study, the effect of cell phone microwaves on sperm parameters and total antioxidant capacity was investigated with regard to the duration of exposure and the frequency of these waves. This experimental study was performed on 28 adult male Wistar rats [200-250 g]. The animals were randomly assigned to four groups [n=7]: i. control; ii. two-week exposure to cell phone-simulated waves; iii. three-week exposure to cell phonesimulated waves; and iv. two-week exposure to cell phone antenna waves. In all groups, sperm analysis was performed based on standard methods and we determined the mean sperm total antioxidant capacity according to the ferric reducing ability of plasma [FRAP] method. Data were analyzed by one-way ANOVA followed by Tukey's test using SPSS version 16 software. The results indicated that sperm viability, motility, and total antioxidant capacity in all exposure groups decreased significantly compared to the control group [p<0.05]. Increasing the duration of exposure from 2 to 3 weeks caused a statistically significant decrease in sperm viability and motility [p<0.05]. Exposure to cell phone waves can decrease sperm viability and motility in rats. These waves can also decrease sperm total antioxidant capacity in rats and result in oxidative stress